Circuit breaker



Allg- 2, 1932- o. s. JENNINGS 1,869,563

CIRCUIT BREAKEH` Filed oct. zo. 1930 2 sheets-sheet 1 Y /'Z F- l im f 4/n" v5; if: 451" L d l in l /f33 I V 32 O) D 40 lINVENTOR 40 7 v l-lE'Zz'I/er' S. Jnnz'ngs.

- ATT'ORNEY Aug'. 2, 1932.

o. s. .JENNiNGs 1,869,563

CIRCUIT BREAKER Filed Oct. 20, 1950 2 Sheets-Sheet 2 .5. Ff .6. Fig. 4.g g

Fig a.

Fig. 12.

INVENToR O l Oliver S. Jennings.

- Patented Aug. 2, 1932 UNITED STATES OLIVER S. JE'NNINGS, 0F MANSFIELD,OHIO, AFS/SIGNOR TO WESTINGHOUSE ELIIEK'I'JRIC1 PATENT?. OFFICE &MANUFACTURING COMPANY, A CORPORATION F PENNSYLVANIA CIRCUIT BREAKEE.

Application filed October 20, 1930. Serial No. l489,804.

ditions in either of the three poles of the circuit.

A further object of my inventon is to provide a simplecurrent-,responsive tripping element that may be applied to multi-polecircuit breakers ofstandard construction, and which may be detachablymounted upon the circuit breaker base, in orderto permit o interchangeof current-responsive elements having different operatingcharacteristics.

A further object of my invention is to provide a trip mechanism for acircuit breaker wherein a plurality of cooperating cam elements serve tojointly retain the circuit breaker releasably Y in closed position, andwherein the cam members are retained in latching positionby separateindependently operable current-responsive elements.. Y

A further object of my invention is to pro- -vide a trip mechanism for'a circuit breaker that comprises a minimum number of parts which areassembled in compact arrangement.

In the copending application, Serial No. 480,096, filed by H. D.,Dorfmamon September 6, 1930 andassigned to the assigneeof thisapplication, a trip mechanism for a circuit breaker is disclosed whereina pair of cams serve to releasably retain the circuit breaker in closedposition and are controlled by thermal elements that are responsive tocurrent in the circuit controlled by two poles of a three-pole circuitbreaker.

It-is a further object of my invention to providea cam-controlled tripmechanism wherein a separate cam is provided for two `of the'three'polesof the circuit breaker which are held in operative position by acurrentresponsive member in the third pole of the circuit in order tha'tthe circuit breaker may' Figure 1 is an elevational view, partiallyf insection, of a circuit breaker embodying features of my invention;

Fig. 2 is an enlarged front elevational view of the current-responsivetrip mechanism shown in F ig. l,

Fig. 3 is an end elevation of the trip mechanism shown in Fig. 2,

Fig. 4 is a transverse sectional view through the trip mechanism shownin Fig. 2, taken on the line IV--IV thereof,

e Figs. 5 and 6 are side and end elevational views, respectively, of acam,

Figs. 7 and 8 are side and end elevational views, respectively, of aresetting lever,

i Figs. 9, 10 and 11 are side, end and opposite side elevational viewsof a second of resetting lever, and

Figs. 12 and 13 are side and end elevational views, respectively, of aframe for the circuit-breaker trip mechanism.

Referring `to the drawings., the 4circuit breaker comprises aninsulating base 7 upon which is mounted a sheet-metal-frame structure 8which serves to support the circuit breaker unit the construction ofwhich is similar to that fully described in my copending application nowPatent 1,7 94,901, issued March 3, 1931, and assigned to the assignee ofthis application.

Briefly, the circuit-breaker unit comprises the frame 8 uponv which acradle 9 is pivotedl for rotative movement about the pivot'pin 11. Anoperating arm 12, having a handle 13is pivoted for rotative movementabout the pivot -pin `14, and a pair of tension springs 15 (one of whichis shown) are attached, at their outer ends, to the arm 12 and,

" at their inner ends, to the knee pivot 16 of a pair of toggle links 17and 18 which serve to operate a pivoted switch Varm 19 that is mountedto oscillate about a pivot shaft 21 mounted on the frame 8, the link 17being pivoted to the arm 19 by the pivot shaft 22, and the toggle link18 being pivotally connected to the cradle 9 at the point 23 in the apexof a notch 24 of V-shape in the cradle 9.

The contact arm 19 carries a flexible leaf spring 25, upon the free endof which is mounted a movable contact 26 that isl adapted to engage astationary contact 27.

The cradle 9 is releasably retained in the closed position shown in Fig.2 by means of a latch that will be hereinafter described. Thecircuit-breaker apparatus may be designated as of the tumbler typewherein an over-center ,spring serves to move the contact to open and toclosed positions. As shown in F ig. 1, the contact 26 is 1n openposition and 1s moved to closed position With a snap action when theoperating handle 13 has been moved clockwisel a sufficient distance tomove the outer end of the spring 15 past a center line traversing thepivot shaft 16 and the point 23 referred to above. When this movement ofthe operating handle has been completed. the spring 15 will snap thelower pivot shaft 16 toward the right and straighten the toggle linksfor forcing the contact 26 into the closed position.

When it is 'desired to move the switch to open position manually, theoperating handle 13 is moved to the left or in a counter-clockwisedirection, and, when the spring 15 again passes over the above-mentionedcenter line, the toggle will be broken with a snap action to cause thecontact 26 to be quickly separated from the contact 27.

In the event of an overload or a shortcircuit condition, the latch arm42 is released, in a manner to be hereinafter described, and the springs.15, which are'in extended stressed condition when the circuit breakercontact is closed, cause the cradle 9 to turn in a clockwise'direction,which movement causes breaking of the toggle and the subsequent rapidseparation of the contact 26 from the contact 27.

Since this form of `circuit-breaker apparatus is completely described inthe abovementioned copending application, it is believed that no furtherexplanation of its construction and operation is necessary for thepurpose of this application, which is concerned more with the particularform of current-responsive releasingapparatus suitable for a multi-polecircuit breaker.

However, it is to be understood that the present form of circuitbreaker, as disclosed in Fig. 1, is of the three-pole type in which theoperating mechanism above described is employed for operating threecontact arms 19 that are connected, at their inner ends, by means of aninsulating cross bar 29.

Referring particularly to Figs. 2 and 3, the current-responsive trippingor releasing device comprises a metal frame 31 of U-shape that issecured, by means of screws 32, upon an insulating block or standard 33that is detachably secured to the insulating base 7. A pair of rotatablymovable cams 34 and 35 are mounted on the frame 31, the former beingdisposed between the side flanges 36 of the frame 31 to be turned aboutpivot pin 37, and the latter being mounted between a pair of pivotallymounted links 30 for movement about the pivot shaft 38 thereon. Theadjacent faces of the cams are provided with two arcuate portions 39, asindicated in Fig. 2.

The cams 34 and 35 are normally biased in counter-clockwise andclockwise directions respectively, by helical springs 41 that serve tonormally retain the cams yieldingly .in their open, latch-receivingpositions.

The cradle 9 of the circuit breaker is provided with a latch arm 42 thatis moved into the space between the cam faces when the circuit breakeris moved to closed and to operative position, the inner edge of thelatchA arm 42 being adapted to engage overlapping resetting arms 43 onthe Cams 34 and 35, which move the cams, against the tension of thesprings 41, into the locking positions, as indicated in Fig. 2, wherethey are releasably retained by bimetal elements 44 and 45,respectively, that are of the usual U-shape construction well known inthe art and su ported on the insulating block 40 inserted m base 7. Themovable outer ends of the bimetal elements 44 and 45 are provided withinsulating latch members 46 that engage shoulders 47 on the cams.

It will be noted that the space between the closest cam surfaces of thecams 34 and 35, when the cams are in locking position, is of less widththan the thickness of the latch arm 42, and, consequently, the latch armis retained in closed position so long as the cams are prevented fromturning, or from separating in opposite` directions. However, shouldeither of the cams be released by the outward movement of either of thebimetal elements 44 and 45, its respective spring 41 immediately causesrotation of the cam, which results in widening of the space between thecam faces 39 and consequent release of the latch arm 42 which is of suchyielding construction that it may be deflected laterally a sufficientdistance to clear the cam which remains stationary.

It Will be understood that the bimetal elements 44 and 45 are connectedinseries with their respective contact arms and are heated by currentflowing in the circuit controlled by the contact arm and are, therefore,'responsive to currentv conditions in that circuit. In the event of anoverloador shortthree-pole circuit breaker responsive to eurrent in eachindividual pole of the circuit, a- -third current-responsive trippingdevice is provided for preventing lateral or bodily displacementof thecam 35 that is pivotally mounted on the links 30. This device comprisesa pair' of toggle links 48 and 49 that are pivotally lconnected by aknee pivot shaft 51, the link 48 being mounted for o'scillation aboutthe pivot shaft 37, and the link 49 being pivotally mounted foroscillation about the pivot shaft 38. The links 48 and 49, as indicatedin Figs. 2, 4 andv 7, to'

12, are of VU-shape and are so disposed that a Vportion of the link 48lits between the side members of the link 49 The link 48 isdisposedbetween the side plates 36 of the support 31, and the cam 34 ismounted between the side members of the link 48. The cam 35- is mountedbetween the side members of the link 49 which are disposed between thelinks 30. This arrangement of the links and cams provides a compactconstruction which requires but little space.

The link 49 is provided with a tongue 52 that projects laterally fromone of the side members of the link, and is adapted to engage a latchseat 53 that is mounted upon, and insulated from, the free end of abimetal element 54 of U-shape that is mounted onthe insulating block 33,the tongue 52 being rovided with a rounded end edge that orces thebimetal element 54 outwardly when the link 49 is moved to its operativelatch-retaining position, as shown in Figs.

1, 3 and 4.

The latch member or arm 42 of the cir` cuit-breaker cradle 9 extendsover the link 49 at a point in line with the tongue 52 thereof andengages the link 49 at the points 56 Y (see Figs. 4, 9 and 10) tomovethe link 49l to its latch-retaining position shown in Figs. ,1,3'and 4 when the latch member 42 is moved to its operative position,shown in the same igures.

The bimetal element 54 is connected in series with the contacts of thepole of the circuit bieaker with which it is associated, and

'is deflected outwardly when an overload or short-circuit conditionoccurs in the pole of the circuit vin which it is connected. When thelatch seat 53 clears the eXtreme end of the tongue 52, the toggle linksare moved toward their straightened position by the spring 41 that isattached to the cam 35, and

by the upward force of the cradle 42 thereby forcing-the cam 35 in alateral direction by reason of its pivotal mounting uponthe links 3 0,and thereupon se aratin the arcuate cam surfaces 39 a su cient istanceto permit the latch member 42 to move to its released position, it beingunderstood that there is sufficient flexibility in the member 42 andsuilicient lost motion in its mounting to permit of the necessarylateral displacement to clear the then non-rotatable cam 34.

In the event that the circuitbreaker is opened asv a result of operationof the bimetal element 54, the cam 35 will be returned to itslatch-retaining position by reason of the engagement of the latch member42 with the arm 43 of the cam 35 and the link 49 of the toggle. When thecam 35 is returned to its original latch-retaining position, it will beretained in that position by the bimetal elements 45 and 54, from whichit has not been freed in the above operation, and which serve toreleasably retain the cam 35 and the tongue 52 in operativelatch-retaining position. It is apparent from the foregoing that, /whenan overload or short-circuit condition .occurs in a circuit connected toany one of the three-poles of the circuit breaker,ithe latter will be'tripped or released to open position and that, regardless of whichcurrentresponsive thermal element functions to cause opening of thecircuit breaker, those elements are resetautomatically when thecircuit-.breaker latch member 42 is moved to its operative position.-

The various elements constituting the tripping mechanism, vincluding thebimetal elements and the frame 31 that are mounted on the block 40,-maybe removed from the supporting base 7 of the circuit breaker withoutnecessitating removal of the circuit breaker from its support, becauseofthe manner in which the cradle 42 is associated with the cams 34 and35.

Current-responsive calibrated trip elements having different responsivecharacteristics may be interchanged for changing the operatingcharacteristics of the circuit breaker to meet the requirements of thecircuits being controlled.

While I have. illustrated but one embodiment of my invention, it' willbe apparent to those skilled in the art that various changes,modilications, substitutions, additions and omissions may be made in theapparatus illustrated without departing from the spirit and scope of myinvention as set forth in the appended claims.

I' Vclaim as my invention:

1. The combination with a trip member for a multi-pole circuit breakerand a pair of vcooperating current-responsive cams for releasablyretainingV thetrip member in operative position, of a thirdcurrent-responsive means for releasably retaining said cams incooperating retaining position and means for resetting all of saidcurrent responsive members to retain said trip member.

2. The 'combination with 'a trip member for a multi-pole circuit breakerand a pair of cooperating curient-responsive members for releasablyretaining the trip member in operative position, of a thirdcurrent-responsive means for releasably retaining the second saidmembers in cooperating retaining position and means operated bynlovement of the circuit breaker for resettingr said current responsivemembers to retain said trip member.

3. The combination with a trip member for a multi-pole circuit breakerand a pair of cooperating members each responsive to current controlledby a separate pole of the circuit breaker, of means responsive tocurrent controlled by another pole of the circuit breaker for releasablyretaining the second said members in cooperating retaining position.

4. 'lhe combination with a trip member for a circuit breaker and a pairof cooperating independently rotatable current-responsive members forreleasably retaining the trip member in operative position and adaptedto permit releasing movement of the said member when either of thesecond said members is rotated and when one'of the second said membersis moved bodily, of current-responsive means for releasably preventingbodily movement of the last said member.

5. The combination With a trip member for a circuit breaker and a pairof cooperating independently rotatable members for releasably retainingthe trip member in operative position and adapted to permit releasingmovement of the said member when either of the second said members isrotated and When one of the second said members is moved bodily, ofindependently operable current-responsive means for releasablypreventing rotary movement of the second said members, and anindependently operable current-responsive means forreleasably preventingbodily separation of the second said members.

6/A trip device for a multi-pole circuit breaker, comprising a latchmember for the circuit breaker, a pair of cooperating rotatable camshaving proximate faces for engaging and releasably retaining the latchmember in operative position when the cam members are moved to latchingposition, and for releasing the said latch member upon rotation ofeither of the cams, the Said. cams being movable to latching position bythe said latch member, independent current-responsive means forreleasably retaining the cams in latching position, a support for one ofthe cams permitting bodily movement thereof for also causing release ofthe said latch member, and current-responsive means for releas- `mountedthereon, a second. cam mounted thereon for rotary and bodily movementfor retaining the latch member in operative osition and for releasingthe circuit brea er by rotary or bodily movement of the cams,

the said cams being operable by the said latchv member, means forbiasing the cams toward unlatching position, independently operablecurrent-responsive means for releasably preventing rotary movement ofthe said cams, and a current-responsive means operable independently ofthe last-said means for releasably preventing bodily movement of thesecond said cam.

8. A trip device for a multiole circuit breaker comprising a latch memer for the circuit breaker, a. cam pivotally mounted thereon, a linkpivotally mounted on the support, a second cam pivotally mounted on thelink for cooperating with the first cam for releasabl y retainin thelatch member in operative position an for releasing the latch memberwhen either cam is rotated and when the second cam is moved bodily awayrom the first cam, means tending to rotate the cams toreleasing'position and to bodily move the second cam, means on the camsengageable by the latchfmember for moving the cams to latch-retainingposition, means connected to the said link for releasably preventingbodily movement of the second cam and operable by the latch for bodilymoving the second cam to latch-retaining position, and se l aratecurrent-responsive means for releasabl)y preventing rotary and bodilymovement of the cams.

In testimony whereof, I have hereunto subscribed my name this 3 day ofOct., 1930.

OLIVER S. JENNINGS.

cooperation with the first cam for releasably

